SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c185159501b232c98f3281bc1f04fade717f89a73192268bf635b6bf2b136cd' 
  AND token = 'qbFBCwjNF8khFSRB5N7hq2VkQ5gnjgPDmkyYSCvGyPY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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