SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be5e20a74e26f2cdf1916d29f01554b8cdb0b066010ca4e2cb6e781eaf9fba05' 
  AND token = 'yt4KUP+n8Z/KBb3XYkz67feSr45MFXCV8eodR76BAkA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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