SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9208c18efe208f506e182919d19dc0b3c5cca66572461cdd3ea635017b77df05' 
  AND token = '2xKpXI017IeBCPQAada2bx1GCacKkhfViORkHP77Hvc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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