SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8946170ee485f80ca2cfe3977708475647992268b94ba76dc33e00d8af41575' 
  AND token = 'vpXsKLXAVRW/jYqAOidrYBeOcXB7qJK4W1U8SUURgco=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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