SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd90f3f451aa99d14439f9ea2cacd15d5a2f61093fb021336bb3c22890d0c362c' 
  AND token = 'nYlmWziMfhHV6uPTF/Bw+/OTsy9Y/V7rLVFZoA4vXp0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}