SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b50cd7c4785654690c5f7055d20e07651715fcf10d35881e8479eecd0455a089' 
  AND token = 'ImqrwbvmvROJZQOr9Am2Gc68uB2BxRYtvhJ38zQQzDA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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