SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8cb0b2d2b21c28f7394451010e3ccade714a0f9462d262192603d9cdb428977' 
  AND token = 'V6OFGqwPqZaKwL2DDSHxrXEKnsE1+QC2XsyzaKvLaVw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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