SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd0f02b0a4e8047995433a1886a4dd86eb3a0ea004f26c0b990785ecbc1d5641' 
  AND token = '8K+YOF7GfZNJczU+q7Cg6Tf/sWh8I8KCPjb7uDOsKy4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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